Comparison of disodium cromoglycate, terbutaline and thiazinamium in the prevention of exercise-induced asthma and its relation to non-specific bronchial responsiveness.

The protective effect of pre-exercise treatment with disodium cromoglycate (DC), terbutaline sulphate (TS) and thiazinamium methylsulphate (TM) on exercise-induced asthma (EIA) was investigated. Thirty-one adults each exercised for over 6 min on a bicycle ergometer. Each subject performed five tests. The first and last exercise tests served as controls. A profile of bronchial reactivity based on the combination of hyperreactivity - as measured by acetylcholine (a), histamine (h) and propranolol (p) - was drawn up. The following combinations and frequencies were based on the response (+ or -) in hyperreactivity studies: group (h+, a+, p+) was present in 21 of the 31 patients studied, group (h-, a+, p+) in 6 patients, group (h+, a+, p-) in 2 patients and group (h-, a+, p-) in 2 patients. The proportion of patients effectively protected from their EIA was 80% for TS, 60% for DC and 40% for TM. These findings suggest that there exists a consistent heterogeneity in the patients' response to exercise, possibly related to the individual distribution of receptors leading to bronchial hyperreactivity.